Electrostatic-type electromechanical transducers, such as electrostatic motors and electric generators, which use charged films having the characteristics of semi-permanently carrying an electric charge are known (for example, see Patent Literature 1). Such electrostatic-type electromechanical transducers include charged films made of an electret material, and opposing electrodes facing the charged films. The electrostatic motors generate driving force by using electrostatic attraction between the charged films and the opposing electrodes, whereas the electric generators generate electric power by using electrostatic induction caused by fluctuations of the overlapping area therebetween. Such electrostatic-type electromechanical transducers are relatively compact, and are thus considered for adoption into portable electric equipment, such as a wristwatch, which a human wears and carries.
FIG. 12 is a cross-sectional view showing a principal part of a conventional electrostatic-type electromechanical transducer 200. The electrostatic-type electromechanical transducer 200 includes a movable substrate 101 composed of multiple connecting portions 123, a fixed substrate 103 disposed under and in parallel with the movable substrate 101, charged films 125 respectively provided on the lower surfaces of the connecting portions 123 of the movable substrate 101, and opposing electrodes 129A and 129B disposed on the upper surface of the fixed substrate 103 at intervals so as to face the charged films 125. If the electrostatic-type electromechanical transducer 200 is an electrostatic motor, the resultant force of electrostatic attraction which is caused by the opposing electrodes 129A and 129B and acts on the charged films 125 is the driving force. If the electrostatic-type electromechanical transducer 200 is an electric generator, electric power is taken out from each pair of the opposing electrodes 129A and 129B at the same time, by moving the charged films 125 relative to the opposing electrodes 129A and 129B.